It has become increasingly important, in recent years, to provide a system for anchoring a dental structure, such as a crown, bridge or like array of teeth or a single tooth, in the jaw of a patient. For that purpose, a dental implant may be anchored in the bone tissue of the jaw.
In the past it has been common to form these jaw implants of a substantially cylindrical, conical or screw shaped member or in the form of a blade implant and to anchor the implant in the bone tissue by providing a bore or cavity in the bone tissue.
A superstructure is customarily attached, to the implant usually by means of a screw connection.
To facilitate the anchoring of the implant in the bone, the bone tissue may be induced to grow in and around the implant. In cylindrical implants, the implant diameter substantially matches the bore diameter or is slightly larger so that a press fit can be formed between the implant and the bone tissue. The bone structure may be such that the fit is unsatisfactory or there may be a poor fit as a result of some inaccuracy or failure in the formation of the bore so that the implant is not anchored with sufficient force in the bone tissue or the anchoring force is not uniform all around the implant. In such cases, loss of the implant is possible. If the press fit results in excessive pressure on the bone tissue, however, the latter may be damaged. This can give rise to local mortality of the bone tissue, can interfere with healing of the damage to the bone tissue caused by the implant and ultimately can also result in loss of the implant or some greater injury to the patient.
In cases in which the implant has the configuration of a screw and is anchored in the bone tissue by threading the implant into it, it has been found that resorption of the periimplant bone tissue can occur which must be compensated by new bone growth. This new bone growth, however, takes considerable time and, as a consequence, the period of healing after the insertion of an implant can be considerable.
It is also a drawback of the implant method that the bore may be drilled too deeply. In that case, the hollow of the bone may be penetrated and damage caused to the mandibular nerves.
Finally, in this regard, for each implant bone tissue must be removed to a depth which corresponds to the implant length so that surrounding bone tissue can be significantly traumatized.